Previously, many types of sprinklers have been used to endeavor to provide an effective means for automatically dispensing a flow of water over a given area. Some are fixed and do not rotate, but create a given pattern, while others rotate by the action of a cam follower pivoted into engagement with the flow stream creating the motivating force. A search of the prior art did not disclose any patents that read directly on the claims of the instant invention, however, the following U.S. patents were considered related:
______________________________________ U.S. PAT. NO. INVENTOR ISSUED ______________________________________ 4,462,545 Lourenco 31 July 1984 4,281,793 DeWitt 4 August 1981 3,884,416 King 20 May 1975 2,739,839 Greener, et al 27 March 1956 2,600,987 Gallice 17 June 1952 1,712,523 Schneider 14 May 1929 595,632 Marchi (Italy) 2 July 1959 ______________________________________
Lourenco teaches a spindle having a cam rotatable with the sprinkler head mounted on an upper chamber. A cam follower is pivoted into engagement with the cam by means of hydraulic pressure. A valve key portion constricts the flow of water in a variable manner controlled by the shape of the cam achieving a pattern, such as a square or non-circular configurations.
DeWitt utilizes a vertical axis water sprinkler having an internal control shell rotating a spray head within a fixed housing. The spray pattern is governed by a number of pattern defining plates. An aperture sweeps across the face and edge of the plate rotating the housing in a predetermined manner. Speed is held constant despite changes in output by a friction bearing and shell pressures.
King employs a rotating sprinkler head with a hollow shaft having a restricting port. A port plate has two passageways with a central port aligned with the axis of rotation and another offset therefrom. An orifice plate is held in place by a spring. As the device rotates, the radial reach is varied depending upon the mutual overlap between orifices and ports achieving a square irrigation pattern.
Greener et al applies a fixed sleeve member supported to a body member. A tubular axle is mounted within the sleeve and is restrained against longitudinal movement. The axle has a continuous inlet and auxiliary inlets at prepositioned locations. The device is attached between the water source and a conventional sprinkler head to vary the amount of water at various angular positions in a rotational cycle, thereby creating a predetermined pattern of distribution.
Gallice also provides a device that is connected between the water source and a revolving sprinkler head. This invention also varies the flow to create a predetermined flow pattern.
Schneider teaches steady as opposed to impact rotation with a deflector pivot point near the output end of a hollow flow arm. The deflector butt section inside the arm has a lower moment of inertia than that of the apex section. The butt section has less flow contact area than the flow cross section area to permit butt swivel action. Arm rotation depends on flow pressure force to hold the deflector at a butt stop position. Rotation reversal requires arm contact with an arm stop and sufficient kinetic energy in the apex section so as to swivel the deflector to an opposite butt stop.
The Italian patent issued to Marchi (Montrouge Meter Manufacturing and Gas Works Company, France) discloses a sprinkler having a wedge shaped deflector with the apex moment of inertia nominally equal to the butt moment of inertia. The jet of water hits the deflector causing the swing arm to rock, shifting the arm on the shaft and producing in conjunction with a spring loaded element, step by step impact rotation.